[michele ambrosio]

Any idea about meshing this geometry?
I am not looking for an accurate mesh for the moment.. just need some guidelines to proceed.
The idea is of course to have the mesh more fine close to the sail and coarser away from it. I was thinking about an unstructured mesh, but if anybody knows about a structured one is well accepted.
thanks in advance

michele

[diamondx]

I took a look at you geometry. problem i find is Thickness. it's completely ignoring the geometry inside. This is an interesting case, first time i deal with it. I'm quite sure thickness is the problem. Where did you draw your geometry ? if in Ansys modeler, can you attach an IGES file of your geomtry from design modeler

[michele ambrosio]

Sorry for replying after so many days, but I was busy. Any suggestion is really appreciated

[Ralen]

TRM_SRF has a thickness or it is a surface?

[Far]

it is a surface?


ok it ishttp://www.google.com.pk/imgres?imgu...PUBMAg&dur=350

http://en.wikipedia.org/wiki/Spinnaker

[michele ambrosio]

yes it is only a surface without thickness

[Ralen]

I built the mesh, but how to make fluent or cfx will "see" an impenetrable surface without thickness.

[michele ambrosio]

@ Ralen:
Just give the boundary conditions of the sail as a wall

[michele ambrosio]

Which software did you use for creating the mesh?
thank you a lot in advance for your help

[Ralen]

Originally Posted by michele ambrosio

@ Ralen:
Just give the boundary conditions of the sail as a wall

This for Fluent. And for CFX a message "Select a BC type." Wall is not acceptable.

[Far]

Here are the files.
Need some modifications to improve the quality.

[Far]

pics :

[Far]

[Far]

"Select a BC type." Wall is not acceptable.

Do not specify bc in ICEM. CFX will automatically get the boundary condition using the named selection.

Also use import mesh option in CFX-pre to read the mesh in .cfx or .cfx5

[michele ambrosio]

Thank you a lot it has been very useful!

[Far]

Ralan's topology has the better quality than mine.

Ralan: Could you please check both and indicate what's the difference?


Since your case has surface in 3d , therefore in ICEM one has to explicitly project the faces to the wall of surface geometry.

[Far]

Do not specify bc in ICEM. CFX will automatically get the boundary condition using the named selection.

For example, inlet/in will have the inlet boundary and outlet/out will have the outlet boundary. similarly wall has the wall condition.

If your naming scheme does not fulfil these requirments still, specifying the different boundaries will give you option to select them later in CFX pre.

Just right click on the component(your geometry) in CFX-Pre and insert new boundary. In this way you can specify wall, symmetry etc. BCs for the remaining boundaries.

[Ralen]

Originally Posted by Far

Since your case has surface in 3d , therefore in ICEM one has to explicitly project the faces to the wall of surface geometry.

Yes, I associate the faces to the sail surface.
I built o-grid mesh only for the sail. You built for area around sail. I also used the internal o-grid.

[Far]

Like this ? But still quality is low!!!!

[Far]

Any idea about meshing this geometry?

The mesh extent is not enough in the y- and Z-direction. It is a low velocity simulation and you need at-least 10-15 lengths upstream and 20-25 lengths downstream.